Tri-sodium phosphate hydrate-soap compositions



Patented New 1, 1932 FRANK L. FROST, .13., OF EAST CLEVELAND, OHIO, -ASSIGNOB TO THE GRASBELLI GEMI- CAL COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF DELAWARE TEE-SODIUM PHOSPHATE K YDBATE-SOAP COMPOBITIOKS Ho Drawing.

Tri-sodium phosphate is usually sold as its dodecahydrate, in which form it is, how- .ever, very susceptible to caking into hard,

' out with the tri-sodium phosphate and becomes an integral part of the crystals.

The appearance of the new crystals is quite different from that of straight tri-sodium phosphate dodecahydrate. While both products crystallize in the form of hexagonal prisms, the soap containing crystals have a satin like sheen or luster by which they are easily distinguished from the straight trisodium phosphate crystals. ference between the two products is, however, besides chemical composition, in their behavior towards atmospheric changes. When ordinary tri-sodium phosphate dodecahydrate is exposed to a dry or a hot atmosphere it loses part of its water of crystallization and under moist conditions takes this water up again with formation of new, small crystals which cement together the larger original individual crystals; tri-sodium phosphate crystals which contain a small amount of soap as an integral constituent lose similarly water under drying conditions, but when this water is again taken up no cementing of the larger crystals into solid lumps by formation of small intermediate crystals seems to take place, and an over-dried, soap containing tri-sodium phosphate hydrate can be kept for weeks in a moist atmosphere of, for instance, 90% saturation without substantial caking.

The amount of soap necessary to produce my novel composition does not in any way interfere with the crystallization of the prod- The main dif- Application filed March 26, 1931. Serial No. 525,613.

uct. ()n the contrary, under similar conditions, the soap containing tri-sodium phosphate will develop into larger and.better formed individual crystals than a straight tri-sodium phosphate will do.

The soap necessary to produce my novel composition is added preferably as an aqueous solution to the tri-sodium phosphate liquor before or after concentration and before crystallization. Another convenient method is to add resin acid or fatty acid to the phosphoric acid before neutralization, and then produce the crystals by concentration and cooling of the neutralized acid.

The amount of soap which can be made to crystallize out with tri-sodium phosphate hydrate is not very critical, and crystals with a satin like sheen are already obtained when the product contains around of the soap. For practical purposes amounts of less than 1% soap are preferred, and about 0.3% oleic acid soap is an amount which .produces a beautiful substantially non-caking crystal.

Other soaps, such as stearates, palmitates and resinates produce quite similar looking products. The soap seems to be homogeneously distributed through the crystals and forms an integral part thereof.

Instead of allowing the tri-sodium phosphate soap composition to crystallize from a concentrated solution and separating the crystals from the mother liquor, it is also possible to spray such a solution and thereby obtain evaporation of water and cooling to produce the same composition of matter.,

The composition of crystals is not necessarily exactly that of dodecahydrate. As is well known in the art the water content of tri-sodium phosphate polyhydrates, that is to say those which contain more than one molecule of water of crystallization, depends upon atmospheric conditions, and in the case of the dodecahydrate may vary a few per cent above or below the value for 12 111015 of crystal water. The same is true with my novel soap containing t-ri-sodium phosphate crystals, which can contain more or less water of crystallization than corresponds to the dodecahydrate without losing their substantially non-caking properties.

and less than 1% of a fatty acid soa ,induc ing formation of tri-sodium phosp ate hydrate-soap crystals therein and separating the crystals from the mother liquor.

'3. A co-crystallized tri-sodium phos hate hydrate-soap composition, the crysta sv of which have a satin like sheen or luster.

4. A co-crystallized tri-sodium phosphate hydrate-soap composition in which the soap is a constituent part-of the individual crystals, the crystals having a satin like sheen or luster.

5. A co-crystallized tri-sodium 'phosphate hydrate-soap composition in which the soap n is distributed throughout the body of the individual crystals, the crystals having a. satin like sheen or luster.

6. A co-crystallized tri-sodium phosphate hydrate-fatty acid soap composition in which the soap is a constituent partof the individual crystals in an amount of not more than 1%, the crystals having a satin like sheen or luster.

7. A eo-crystallized tri-sodium phosphate dodecahydrate-soap composition in which about 0.3% of sodium oleate is a. constituent part of the individual crystals, the crystals having a satin like sheen or luster.

8. A co-crystallized tri-sodium phosphate dodecahydrate-soap composition in which about 0.3% of stearic acid soap is a constituent part of the individual crystals, the crystals having a satin like sheen or luster.

In testimony whereof, I aflix my signature.

FRANK L. FROST, JR.

memos 

